Interpretive Summary: This article summarizes greenhouse gas research results from studies conducted from 2002 through 2008 near Fort Collins, CO by the USDA, Agricultural Research Service. Research results evaluating the effects of tillage, N rate and source, and cropping system on growing season nitrous oxide (N2O) emissions show that application of N fertilizer increases N2O emissions linearly from irrigated cropping systems in Colorado. Conventional-till continuous corn had a higher level of N2O emissions than no-till continuous corn. Inclusion of soybean or drybean in the no-till corn rotation increased the level of N2O emissions during the corn year of the rotation. Use of controlled release and stabilized N sources reduced N2O emissions under no-till when compared to urea and UAN fertilizer sources. Results of this work indicate that there are crop and fertilizer N management alternatives to reduce N2O emissions from irrigated systems.

Technical Abstract:
This article summarizes greenhouse gas research results from studies conducted from 2002 through 2008 near Fort Collins, CO by the USDA, Agricultural Research Service. Research results evaluating the effects of tillage, N rate and source, and cropping system on growing season nitrous oxide (N2O) emissions show that application of N fertilizer increases N2O emissions linearly from irrigated cropping systems in Colorado. Conventional-till continuous corn had a higher level of N2O emissions than no-till continuous corn. Inclusion of soybean or drybean in the no-till corn rotation increased the level of N2O emissions during the corn year of the rotation. Use of controlled release and stabilized N sources reduced N2O emissions under no-till when compared to urea and UAN fertilizer sources. Results of this work indicate that there are crop and fertilizer N management alternatives to reduce N2O emissions from irrigated systems.